二律背反: (philosophy) antinomy

市立: (attributive, government, of an institution) the state of being established by a city's government; municipality

自立語: (grammar) independent (freestanding) word, substantive

run into, hit, strike

see you later (said by a person leaving, a stock phrase required by the Japanese etiquette, lit.: (after) going, I will come back)

(humble) alternative form of いってきます (itte kimasu)

back and forth

(colloquial) Synonym of 行って来ます (itte kimasu, “see you later”)

to go and come back

not straightforward; not dealt with by ordinary means